Power tool

摘要

A power tool has a casing and a motor assembly installed within the casing. The motor assembly comprises a motor, a heat dissipation device, a fan and a guiding member. The motor has a stator and a rotor. The heat dissipation device has an annular heat absorbing section which is fitted to a housing of the stator and a plurality of fins extending from the heat absorbing section for dissipating heat. Air flow generated by the fan is guided to the fins of the heat dissipation device by the guiding member to cool the motor.

主权项

1. A motor assembly comprising:
a motor comprising a stator, a rotor installed inside the stator, and an airflow passage formed inside the motor, the airflow passage having two axial ends both being open to communicate with outside of the motor; a heat dissipation device disposed on a radially outer surface of the stator for absorbing heat from the stator, a fan attached to the rotor and located outside of the motor adjacent to one axial open end of the motor for generating an airflow to pass through the airflow passage inside the motor; and a guiding member arranged at one end of the motor and configured to guide the airflow generated by the fan to the heat dissipation device on the radially outer surface of the stator, wherein the airflow generated by the fan enters into the airflow passage inside the motor from outside of the motor via the other one axial open end of the motor away from the fan and exits the airflow passage via the one axial open end of the motor adjacent the fan, the airflow reaches the fan located outside of the motor after exiting the airflow passage inside the motor and is then guided to the heat dissipation device by the guiding member.